What is being described as the first practical guide to ensure the safe use of flavors in electronic cigarettes has been published by Nicoventures, a nicotine company established by British American Tobacco (Regulatory Toxicology and Pharmacology DOI: 10.1016/j.yrtph.2015.05.018).
A BAT press note said today that while electronic cigarettes and other vapor products delivered nicotine without smoke toxicants, some in the public health community had expressed concerns over the potential health impacts of flavors used in electronic cigarettes. Consequently, the British Standards Institute (BSI) was developing product standards for electronic cigarettes that would provide guidance on manufacturing, testing and safety requirements.
These guidelines laid out the “what” (including the toxicological risk assessment of flavors), said Dr. Sandra Costigan, the principal toxicologist at Nicoventures, while the new guide provided the “how”.
The flavors typically used in electronic cigarettes are food grade, which means that they have been generally ingested rather than inhaled. “This means that the data available is oral and there are large data gaps,” said Costigan, who is a member of the BSI steering committee on electronic cigarettes. “Safe to eat is not the same as safe to inhale. “The data gaps need to be filled.
“In the meantime, what are the kinds of data sources, approaches and scientific rationale that will allow us to determine if we can use a flavor and at what level? This guide explains how to do that.”
The first step apparently is to ensure that any flavors are food grade and to screen out any potential carcinogens or respiratory allergens. “At this stage, in the absence of inhalation data we make quite a lot of use of what are called TTCs or Toxicological Thresholds of Concern,” said Costigan. “TTCs are used by agencies like the WHO and FDA and they basically help define how much of something can be used in the absence of other toxicity data. We use TTCs to determine how much of any particular flavor ingredient can be used.
“The next step is to assess the compounds produced as a result of heating these flavor molecules, as it is the ‘vapor’ – i.e. the aerosol produced on heating the e-liquid – that consumers are exposed to, not the e-liquid itself. Here we are dealing with new compounds and potential thermal breakdown products, rather than ingredients, and so our approach to acceptable levels will be different.
“None of the draft standards and regulations tell us how to do such a risk assessment, and the scientific literature thus far has focused on problems, such as lack of inhalation data, rather than solutions. Ours is the first sensible and practical guide to help actually conduct such a risk assessment on the flavors, based on sound toxicological principles,” said Costigan.